Linux kernel mirror (for testing)
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1#ifndef _LINUX_RMAP_H
2#define _LINUX_RMAP_H
3/*
4 * Declarations for Reverse Mapping functions in mm/rmap.c
5 */
6
7#include <linux/list.h>
8#include <linux/slab.h>
9#include <linux/mm.h>
10#include <linux/spinlock.h>
11
12/*
13 * The anon_vma heads a list of private "related" vmas, to scan if
14 * an anonymous page pointing to this anon_vma needs to be unmapped:
15 * the vmas on the list will be related by forking, or by splitting.
16 *
17 * Since vmas come and go as they are split and merged (particularly
18 * in mprotect), the mapping field of an anonymous page cannot point
19 * directly to a vma: instead it points to an anon_vma, on whose list
20 * the related vmas can be easily linked or unlinked.
21 *
22 * After unlinking the last vma on the list, we must garbage collect
23 * the anon_vma object itself: we're guaranteed no page can be
24 * pointing to this anon_vma once its vma list is empty.
25 */
26struct anon_vma {
27 spinlock_t lock; /* Serialize access to vma list */
28 struct list_head head; /* List of private "related" vmas */
29};
30
31#ifdef CONFIG_MMU
32
33extern kmem_cache_t *anon_vma_cachep;
34
35static inline struct anon_vma *anon_vma_alloc(void)
36{
37 return kmem_cache_alloc(anon_vma_cachep, SLAB_KERNEL);
38}
39
40static inline void anon_vma_free(struct anon_vma *anon_vma)
41{
42 kmem_cache_free(anon_vma_cachep, anon_vma);
43}
44
45static inline void anon_vma_lock(struct vm_area_struct *vma)
46{
47 struct anon_vma *anon_vma = vma->anon_vma;
48 if (anon_vma)
49 spin_lock(&anon_vma->lock);
50}
51
52static inline void anon_vma_unlock(struct vm_area_struct *vma)
53{
54 struct anon_vma *anon_vma = vma->anon_vma;
55 if (anon_vma)
56 spin_unlock(&anon_vma->lock);
57}
58
59/*
60 * anon_vma helper functions.
61 */
62void anon_vma_init(void); /* create anon_vma_cachep */
63int anon_vma_prepare(struct vm_area_struct *);
64void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *);
65void anon_vma_unlink(struct vm_area_struct *);
66void anon_vma_link(struct vm_area_struct *);
67void __anon_vma_link(struct vm_area_struct *);
68
69/*
70 * rmap interfaces called when adding or removing pte of page
71 */
72void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
73void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
74void page_add_file_rmap(struct page *);
75void page_remove_rmap(struct page *);
76
77/**
78 * page_dup_rmap - duplicate pte mapping to a page
79 * @page: the page to add the mapping to
80 *
81 * For copy_page_range only: minimal extract from page_add_rmap,
82 * avoiding unnecessary tests (already checked) so it's quicker.
83 */
84static inline void page_dup_rmap(struct page *page)
85{
86 atomic_inc(&page->_mapcount);
87}
88
89/*
90 * Called from mm/vmscan.c to handle paging out
91 */
92int page_referenced(struct page *, int is_locked);
93int try_to_unmap(struct page *, int ignore_refs);
94
95/*
96 * Called from mm/filemap_xip.c to unmap empty zero page
97 */
98pte_t *page_check_address(struct page *, struct mm_struct *,
99 unsigned long, spinlock_t **);
100
101/*
102 * Used by swapoff to help locate where page is expected in vma.
103 */
104unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
105
106/*
107 * Cleans the PTEs of shared mappings.
108 * (and since clean PTEs should also be readonly, write protects them too)
109 *
110 * returns the number of cleaned PTEs.
111 */
112int page_mkclean(struct page *);
113
114#else /* !CONFIG_MMU */
115
116#define anon_vma_init() do {} while (0)
117#define anon_vma_prepare(vma) (0)
118#define anon_vma_link(vma) do {} while (0)
119
120#define page_referenced(page,l) TestClearPageReferenced(page)
121#define try_to_unmap(page, refs) SWAP_FAIL
122
123static inline int page_mkclean(struct page *page)
124{
125 return 0;
126}
127
128
129#endif /* CONFIG_MMU */
130
131/*
132 * Return values of try_to_unmap
133 */
134#define SWAP_SUCCESS 0
135#define SWAP_AGAIN 1
136#define SWAP_FAIL 2
137
138#endif /* _LINUX_RMAP_H */